Hey all, I have the 2013 11" MBA (i5, 128GB & 8GB RAM) and I have found an interesting (and annoying) issue. This has happened twice now.... With more than 80 percent charge left I shut the lid and put it to sleep yesterday afternoon. I then put it in a sleeve and then into my Muzetto bag and put it in my car. I am a computer guy--driving around fixing PC's and Macs and networks and stuff--but I don't always need my laptop with me in the client's office or house, so I sometimes leave it in the car. Today it was in the car most of the day (under the seat, not in direct sunlight) and I went to get it out this afternoon to troubleshoot a router. It had been asleep for about 24 hours, I would guess. And it was pretty hot. (I live in Phoenix, AZ--it was like 107 today.) I brought it in, pulled it out of the case & sleeve, let it sit for fifteen minutes or so to let it cool down and then opened it. Totally dead battery. Hit the power button, got a quick flash of the critical red-low-bat symbol and it died. I then plugged it in, and powered it on. I-Stat said it was about 66 deg C so it was not too hot. But, it wasn't charging--got a message in the menu bar saying it was not taking a charge. I had to shut it down, then reboot it, and then it finally showed that it was taking a charge. Everything has been fine since and it worked flawlessly for the rest of my appointment. This also happened once a about three weeks ago, also on a hot day, but I thought it was my error, maybe letting it sit too long asleep. (Though it had only been like two days, and these new Haswells are supposed to last for a week or two I thought.) And today, it had barely been 24 hours or less. Went from 80% with the lid closed to 0. I'm blaming the heat... but I'm just guessing. Something to do with heat and sleep. Somehow it's waking up even with the lid closed inside my case? For now, I will just power it off instead of letting it sleep. Just wondering if anybody else noticed this issue. My 2011 11" Ultimate Air never exhibited this behavior and I treated it just the same over the last two summers.